Describing machining operations: Educate a tyro please!

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mcdanlj

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I am experiencing web search failure. I expect that if I knew what search terms to use, I wouldn't need to search in the first place...

As a hobbyist, I have picked things up from web pages, blogs, and videos, like many other hobbyists. I would like to be able to describe the series of operations I use to make a part in a way that a machinist, hobbyist or otherwise, could clearly understand. I expect that there is a standard form for describing a series of operations. I looked through the stickies in this forum and see glossaries (including common abbreviations) but didn't see a norm or standard for describing machining operations.

I'd like to be able to express the operations I used to make a part in a standardized and unambiguous way that others would be able to use, with a print, to make the same part I made in the same way (or to intentionally do it a different way...)

As a concrete example, here's a plan I made for myself, just to describe for myself how I wanted to make a part.
  1. 1 7/8" stock in lathe, face for Z reference station
  2. Center drill #5, drill up to 37/64 to depth 1.4"
  3. Turn station 0 - 1.500 diameter 1.600
  4. Turn station 0 - 0.39 diameter 1.02
  5. Turn 20⁰ taper from station 0.94 past station 0.39
  6. Part at station 1.200 diameter 1.4
  7. Turn station 1.200 - 1.500 diameter 1.4
  8. Saw to finish cut at 1.5"
  9. Part in dividing head, 20⁰ up, indexed to back of 1.200 station part, jaws holding 1.4 diameter shaft at back of prat
  10. Center Y on part, Zero X to top of end of part
  11. At station 0.74", mill flats 0.6 wide (X), 0.03" deep every 60⁰
  12. Center drill, drill to R for M10 at X station 0.74" every 60⁰ (in the middle of flats), tap M10
  13. Dividing head to 0⁰, zero X to end (lathe Z reference station)
  14. Mill flats every 60⁰ aligned with holes, 0.875" across flats, 0.40" on X
  15. Re-mount in lathe reversed, jaws holding flats, index Z zero to back previously 1.200 station
  16. Face at 0.000 station
  17. Bore to 0.80" diameter to 0.60" depth
  18. Tap remaining hole through 5/8-18
  19. Bore diameter 1.438 to 0.260" depth (critical dimensions)
  20. Counter-bore additionally by tool radius
This is obviously not comprehensible without reference to a print, and that seems OK to me. But it is ambiguous, includes lots of noise words, bundles multiple operations together, and screams "tyro" in every line. I'd like to learn to do better.

What terms do I search for to learn how to do this right?

Thanks! ☺
 
Have you checked out "That Lazy Machinist"? Here is link to operations sequence.
. This is a 3 part series. Middle of part 2 he shows a form that can be filled out with the information needed to perform operation. I have watched almost all of his stuff at one time or other.
A lot of what you have written above is shown on the drawing. Some of the stuff should be in notes on the drawing. Your operations should only reference doing it, not all the dimension and lengths. Nothing wrong with it, just extra words. If you are trying to show a complete novice how to do it then you will need to add extra detail in over and above what you have. Note 13, you are touching off to end of shaft on a mill, but, you didn't say how to position the dividing head and shaft on the table. You assumed the person would orient it in the X axis. Also nothing said about dialing it inline with the bed. If it is .050 out of line all of your operations will be crooked.

I don't know if you really want to search for "terms". Usually the sequence is up to the machinist doing the job. If you know of a trouble spot, you might want to note it in written notes or comments. Me, I would have turned all the straight diameters at one time and the taper last because you have to change the compound, but that's me.

Your description is detailed enough that I could make the part from it lacking a drawing. With a drawing, I would consider it over kill.
Hope this helps, not hurts. Charles
 
Thanks! Looking forward to watching that.

(I was guessing that there was a standard language used when filling in a form like that, and that there was a standard name for those kinds of forms. I'm used to standardized shorthand jargon in other disciplines.)
 
I don't think there is such a thing as a Machinists language to describe sequence of operations, other than the standard terms such as face, turn, bore, etc. Also, I have never seen anyone publish such a sequence in a formal way, that is in supplement to the drawings. Usually, as Chewy noted, It is up to the Machinist making the part to determine the sequence of operations.

IMHO, a drawing should always be provided if asking someone else to make a part for you. With a clear drawing such added descriptions are unnecessary. However, for the one making the part it may be helpful to make such a list, but it only needs to make sense to themselves.
 
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The whole thing for sequence of operations is how to hold the part or reference the part for the operation. If you watch the "established" You Tubers, everyone of them have a couple of videos where they got the sequence wrong and had to compensate or in some cases start over. That is a fact of life in this hobby/business. The more experience the less mistakes AND the better your ability to salvage a mistake and make it right.

Good Luck!! This is a fun, rewarding hobby when you can hold something that you make and everybody else is envious. I make tools and gadgets and repair things mostley. Starting on steam engines now. I like HO trains, but I buy them. I will MAKE the steam engines from raw material and then sit there and watch them chug. I bet a lot of people reading this know what I'm saying. Charles
 
Eddyde said:
It is up to the Machinist making the part to determine the sequence of operations.
Click to expand...

Yeah, I really had two completely separate goals here. In both cases to clearly and concisely:
  • Summarize a plan for myself, to follow or to modify on purpose while making a part, in a way that's easy to follow when I'm standing at the lathe and mill.
  • Communicate with other (hobby, in my case) machinists about the process I used to make a part, to help learn from each other.
When I was actively flying (personal, not professional) I was used to a standardized shorthand for air traffic control clearances that let me unambiguously write down a plan, or a change in plan, with one hand, while flying the airplane with the other. Another pilot in the right seat would be able to glance at my notes and immediately and unambiguously know exactly what the plan was.

Eddyde said:
IMHO, a drawing should always be provided if asking someone else to make a part for you.
Click to expand...

Of course. My question was for making my own parts though. ☺ I'd like to be able to say "Here's the print, here's a picture of the part, and here's how I made it" competently.
 
Understand where you are coming from, but it is different in hand crafted stuff. As pointed out by numerous You Tubers, put 10 machinists on a part and have 11 different ways to do it. You want more of a description of how you did it than a sequence of operation. That would be better as a text paragraph detailing how you proceeded and any problems that you encountered. Similar to reading an article in a magazine but shorter.

As pointed out above, we face, bore, turn, indicate, ream. contersink, counterbore, etc. Just knowing what the terms are gives some of the needed operations. Hope this helps! Charles
 
Removing ambiguity in terminology would be a massive undertaking.

I've done setup sheets for many years, taking pictures of the work holding and tooling helps quite a bit with that. Machinists aren't typically known for their grammar skills.
 
I think this is one of those "learn by example" areas - find a bunch of project/job descriptions, and copy what they do.

Unfortunately, most of the stuff online is of the "here, watch my video" variety. Even the Tormach project library is surprisingly informal.

The Village Press Project books and some of the Model Engineer Workshop series provide pretty good descriptions. There is also an old textbook, Advanced Machine Work (ISBN 978-0917914232), that provides lots of "schedule of operations" descriptions that sound like just what you are in need of.
 
In the aviation world everything is based on more or less standard checklists, and communication with ATC is designed to pack the maximum information into the fewest words possible to keep radio transmissions short. Every pilot is trained to understand and use a standard shorthand.

Unfortunately no analog exists in the machining world. Operations are pretty well defined by descriptive nomenclature (face, bore, drill, ect.). But order of operation is many times dictated by the part. Many times figuring out how to hang on to the part while performing an operation is the biggest challenge.

I have never seen a written order of operation quite as granular as yours, but we all do (or should be doing) pretty much the same thing. For simple jobs I may create that checklist in my head while moving from the bandsaw to the machine with the raw material, for more complex parts, I may spend more time ''machining'' the part in my head than actually making chips. Sometimes I make notes on the drawing, but normally would not do a complete written order of operation. You don't want to paint yourself into a corner, and want to minimize resetting the part and tool changes for the next operation(s).

The only time I actually use a setup sheet is in CNC work. There the tools and offsets are listed, material, raw stock size, and any special information is noted on my standard setup sheet file that travels with the G code program, the part drawing files are also stored in the same folder. Most of the information is automatically generated and filled in when setting up the job the first time. The operation definitions (human readable) and order of operation is defined in the G code program, and determined while safely sitting in front of a computer with the CAM program and running tool path simulations to make sure nothing bad is going to happen and that the end result is satisfactory.
 
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